So I am getting this error as well, it has happened now in my two most recent saves. It seems to be proceeded by a weird separate issue but it is how I discovered the manage worlds -> game load error. Although, I was not having this issue with manage worlds moving households until this other bug occurred first in both instances.
In both of these saves for some reason family members (teens or younger) will randomly be moved out of their default homes (at least one parent/older sim is still there so there is no reason for them to be moved). In one case neighborhood stories was turned on for the family (the Delgato household) but moving out was turned off. In the second case (the Goth household), neighborhood stories was completely turned off and yet randomly cassandra and alex were moved into other households (separately) leaving Mortimer and some infants left in the Goth house.
The error occurs every time after trying to move the sims back into their original household from manage worlds. I have tested it with and without mccc and get the same error. Now the moving bug itself could be mccc related (i don't really know how to test that given the randomness of it and it only started happening after a recent patch) but the manage worlds -> game load error seems to be a game bug and not mod related.
